1. Field of the Invention
The present invention relates to porting of the propellant gas of a firearm and, more particularly, to the reduction of gun rise, muzzle jump and lateral motion of a firearm through porting of the propellant gas.
2. Description of Related Art
Handheld firearms, when fired, exhibit a phenomenon usually described as muzzle jump. The common intuitive understanding of the phenomenon has provided guidance for gunsmiths and inventors who have generated numerous devices intended to reduce the magnitude of the normal upward pivotal motion of the muzzle by venting the propellant gas upwardly at the muzzle to create a downward thrust on the muzzle. The ultimate purpose of these devices was and is that of permitting firing a series of shots more rapidly and accurately.
A better understanding of the phenomena which interfere with the rapid shooting of the firearm is required to more accurately address a solution. Central to this increased understanding is the concept that the phenomenon of gun rise is separate from the phenomenon of muzzle jump. Gun rise is an upward motion of the entire firearm when it is fired which would occur even if muzzle jump were completely eliminated. This concept of gun rise is not addressed in the known prior art.
Gun rise is a small upward motion of the firearm which interferes with the aiming of the firearm when several shots are fired from the firearm in quick succession. Gun rise motion occurs after the well known muzzle rise motion. Virtual elimination of gun rise permits the shooter to fire a series of shots rapidly and more accurately than is otherwise possible.
If only muzzle jump and gun rise were present when a handgun is fired, one would expect an experienced shooter to be capable of adapting his/her technique to bring the handgun back on target. Relatively little mental computation would be necessary and the assumed automatic return to the original shooting position would naturally improve the speed and accuracy of a subsequent shot. Unfortunately, the real situation differs considerably from the simplified assumption that only muzzle jump and gun rise are present and return of the handgun to its prefiring position is often not realized in practice. Several factors can produce muzzle motion which is angled laterally considerably from motion in a vertical plane. The subsequent path of the muzzle can be somewhat circular and it is difficult to accurately return the handgun to the original shooting position.
When shooting a semi automatic handgun, the combination of the positioning and holding power of the hands combined with the positioning of the wrist, as well as the elbow and shoulder, will normally produce muzzle motion which is not vertical. This is partly due to the effective point of support for the handgun being located to the side of the vertical plane of symmetry of the handgun. The resulting sideways component of muzzle motion changes the simple vertical one dimensional motion into a two dimensional motion which demands considerably more mental computation to track and compensate for the muzzle motion. Upon analysis it has been determined that the following causal factors are present: 1) the rotational stiffness, in the vertical plane of symmetry of the handgun and resulting from the shooter's hold of the handgun, is usually different from the rotational stiffness in the horizontal plane; 2) the rotational stiffness in the vertical plane and the horizontal plane are likely to be non linear; and 3) the errors and non linearities of the human response/reaction in the horizontal and vertical planes will produce a muzzle motion which is somewhat circular and which is not likely to return the muzzle to the original shooting position. The lateral movement of the handgun in combination with the vertical movement of the handgun increases the time required to return the handgun to the target for the following shot and tends to decrease the accuracy of the following shot(s).
The known prior art is directed to reduction or elimination of muzzle jump. Generally the muzzle jump is sought to be countered by the installation of ports directly into the barrel near the muzzle to vent the propellant gas directly into the atmosphere. Numerous variants of such vents exist for rifles and non semiautomatic handguns. Radial (upward, lateral and/or downward) porting of propellant gas from the barrel near the muzzle through simple ports allegedly reduces muzzle jump or allegedly reduces recoil by reducing the propellant gas pressure in the barrel before the projectile leaves the muzzle. Upward porting of the barrel near the muzzle with side by side paired ports with each port of each pair being equally spaced from a vertical plane coincident with the axis of the barrel is a well known variant which allegedly helps reduce muzzle jump. In some embodiments, the propellant gas may be vented radially (laterally) in opposing directions, without upward venting at the muzzle. Another approach includes using radial (lateral) ports disposed in the barrel between the chamber and muzzle to vent the propellant gas posteriorly on each side to help reduce recoil. Finally, it is known to use radially oriented, backward facing and diverging paired ports spaced from near the chamber to near the muzzle to symmetrically vent the propellant gas simultaneously in different directions to generate equal opposing forces.